IUN or International University in Geneva (IUG), I would say is the best university in Geneva. I myself an MBA student at IUG who joined this university half my way through the BBA, to study Finance and Accounting. The reasoning behind my decision was IUG's reputation, faculty, accreditation, and alumni.
The university's reputation is great and some large companies recognize IUG as the top business school in Geneva. When you apply for large companies, in the application section where you have to select the university where you graduated, you find IUG on the list most of the time.
Attention! this is a UNIVERSITY not a school, and provides higher education for bachelor's, master's and doctorate degrees. For example if you graduate with a Bachelor's from IUG you can easily get into LSE, it all depends on your grades. The university has a strong network and university partners across the globe. Moreover, professors at IUG hold doctorates from prestige universities like Oxford, and are well known economists that publish their articles that are picked up by the large companies and central banks.
The International University in Geneva was created 20 years ago and is ranked 7th best Business School in Switzerland by EDUNIVERSAL. It is accredited by the the Accreditation Council for Business Schools and Programs (ACBSP) - recognized by the Council on Higher Education Accreditation (CHEA) in the USA, and by the International Assembly for Collegiate Business Education (IACBE).
BE CAREFUL!!!! When you look for University in Geneva or any other canton in Switzerland, you have to check if they are accredited and recognized.
Some of the IUG graduates have achieved a lot in their careers, and some of them take executive positions in large companies, for example CEO of UBS Zurich bank, or financial advisory on CNBC channel. But, again it depends on you, the world is your oyster, and it all depends on you. Since IUG represents students from more than 60 countries, it provide you access to global network that is so essential for your career.
Regarding your question, yes IUG worth of considering, and they are very strong academically in both IR and diplomacy.
Regards
All the best with your studies!